1. Field of the Invention
This invention broadly relates to orthodontic indirect bonding apparatus that is useful for affixing orthodontic appliances to a patient's teeth. More particularly, the present invention is directed towards orthodontic indirect bonding apparatus with structure for controlling moisture in the oral cavity such as saliva during a bonding procedure.
2. Description of the Related Art
Orthodontic treatment involves movement of malpositioned teeth to desired locations in the oral cavity. Orthodontic treatment can improve the patient's facial appearance, especially in instances where the teeth are noticeably crooked or where the jaws are out of alignment with each other. Orthodontic treatment can also enhance the function of the teeth by providing better occlusion during mastication.
One common type of orthodontic treatment involves the use of tiny, slotted appliances known as brackets. The brackets are fixed to the patient's teeth and an archwire is placed in the slot of each bracket. The archwire forms a track to guide movement of teeth to desired locations.
The ends of orthodontic archwires are often connected to small appliances known as buccal tubes that are, in turn, secured to the patient's molar teeth. In many instances, a set of brackets, buccal tubes and an archwire is provided for each of the patient's upper and lower dental arches. The brackets, buccal tubes and archwires are commonly referred to collectively as “braces”.
In general, orthodontic appliances that are adapted to be adhesively bonded to the patient's teeth are placed and connected to the teeth by either one of two procedures: A direct bonding procedure, or an indirect bonding procedure. In the direct bonding procedure, the appliance is grasped with a pair of tweezers or other hand instrument and placed by the practitioner on the surface of the tooth in its desired location, using a quantity of adhesive to fix the appliance to the tooth. In the indirect bonding procedure, a transfer tray is constructed with wall sections having a shape that matches the configuration of at least part of the patient's dental arch, and appliances such as orthodontic brackets are releasably connected to the tray at certain, predetermined locations. After an adhesive is applied to the base of each appliance, the tray is placed over the patient's teeth and remains in place until such time as the adhesive has hardened. Next, the tray is detached from the teeth as well as from the appliances, with the result that all of the appliances previously connected to the tray are now bonded to the respective teeth at their intended, predetermined locations.
Indirect bonding techniques offer a number of advantages over direct bonding techniques. For example, it is possible with indirect bonding techniques to bond a plurality of appliances to a patient's dental arch simultaneously, thereby avoiding the need to bond each appliance in individual fashion. In addition, the transfer tray helps to locate the appliances in their proper, intended positions such that adjustment of each appliance on the surface of the tooth before bonding is avoided. The increased placement accuracy of the appliances that is often afforded by indirect bonding procedures helps ensure that the patient's teeth are moved to their proper, intended positions at the conclusion of treatment.
The control of moisture during a bonding procedure is often deemed important, since the presence of moisture can adversely affect the resultant bond strength between the appliance and the tooth. If, for example, the appliance inadvertently detaches from the tooth during the course of treatment, the patient must often return to the practitioner's office for rebonding of the appliance or replacement of the appliance before full treatment can resume. Obviously, unintentional debonding of orthodontic appliances is a nuisance to both the practitioner and to the patient that is best avoided if at all possible.
In the past, a variety of methods were used to reduce the presence of moisture in the patient's oral cavity during orthodontic bonding procedures. For example, some practitioners use absorbent articles such as cotton rolls to absorb saliva and/or blood along with cheek retractors to help keep the mouth tissue in an open, stationary position. Other practitioners use suction devices such as Nola brand dry field cheek retractors that have suction tubing for drawing fluids out of the oral cavity. Other practitioners have proposed the use of an anti-sialagogue, a drug that can be used to dry the salivary glands during a bonding procedure.
The control of moisture during an indirect bonding procedure is often considered more challenging than controlling moisture during a direct bonding procedure. For one thing, in an indirect bonding procedure, it is important to simultaneously keep multiple bond sites dry. In addition, many indirect bonding trays have interior wall sections that closely fit the patient's teeth, and consequently tend to spread moisture over relatively large portions of the tooth surface as the tray is placed onto the dental arch.